Aclidinium bromide inhibits proliferation of osteosarcoma cells through regulation of PI3K/Akt pathway.

Osteosarcoma is recognized as the most common primary malignant bone tumor, the 5-year disease-free survival rate in patients with metastatic or recurrent disease is below than 30%. Drug resistance and toxic side effects limit the therapeutic efficacy of osteosarcoma. Therefore, it is urgent to develop new drugs for osteosarcoma treatment. Muscarinic 3 (M3) acetylcholine receptor (AChR) has been demonstrated in nonneurocrest-derived malignancies such as colon, prostate, lung, and ovarian carcinomas. Hence, targeted regulation of M3 AChR may be a possible mechanism for treating tumors. Aclidinium bromide has anti-tumoral properties in several tumors, namely gastric cancer and glioma. In this study, we intended to investigate whether aclidinium bromide, a novel M3 AChR antagonist, had effects on osteosarcoma cells proliferation and migration. The viability of U2 OS cells was detected by cell counting kit-8 (CCK-8) assay. The migration and invasion capabilities were measured by transwell invasion and migration assays. The cell apoptosis rate was tested by Annexin V-fluorescein isothiocyanate (FITC)/Propidum iodide (PI) staining and flow cytometry. Key apoptosis-related and phosphatidylinositol-3-kinase (PI3K)/protein kinase B (AKT) signaling pathway-associated were assessed by Western blot analysis. Aclidinium bromide markedly decreased the OD value of U2 OS cells 48 h and 72 h after treatment. The number of positive crystal violet staining cells significantly decreased after treatment with aclidinium bromide. Treatment with aclidinium bromide significantly increased cell apoptosis rate, accompanied by the expression of anti-apoptotic protein Bcl-2 decreased, the expression of pro-apoptotic protein Active caspase-3 and Bax significantly increased in U2 OS cells treated with aclidinium bromide. Additionally, aclidinium bromide suppressed the PI3K/AKT signaling pathway in U2 OS cells. Therefore, the current study reveals that aclidinium bromide might inhibit osteosarcoma cell growth by regulating the PI3K/AKT signaling pathway, which suggests aclidinium bromide is a potential chemotherapeutic agent for osteosarcoma.